Portals or overhead signposts for variable light displays are now widely used along or above the vehicle traffic lanes. To be visible from a long way by the motorists, these structures include at least one vertical support post and a horizontal crossbar supporting a variable-message light display panel arranged high up. Within the context of the invention, the term “structure” must be understood as corresponding to a carrier structure for a variable light display with one, two or more support posts. For a portal above traffic lanes, two posts are erected, on either side of the lanes, to support the light display panel extended transversally above the lanes. An overhead signpost arranged laterally to the lanes includes only one support post. The light display panel is in all the cases electrically power supplied.
Such structures may be arranged at any place and in particular in rural or even desert areas, where the electric power grid is not always established. It has hence been proposed to implement autonomous electric power supply sources, as for example wind turbine or photovoltaic panels.
In practice, the photovoltaic panels are mechanically fixed to the structure. In order to have an optimum efficiency, the photovoltaic panels, which are fixed, are placed so as to be directed towards a zone of the sky where, in average, the solar luminosity is the highest. It results therefrom that, at other latitudes than the equator, the photovoltaic panels must have a relatively significant inclination. In practice, the photovoltaic panels are directed towards the south according to a practically vertical axis.
This leads to two consequences. On the one hand, the photovoltaic panels have hence a significant surface area, possibly cantilevered, and are subjected to wind, which generates high mechanical stresses to the structure and to the ground anchoring concrete pedestals. In order to support these additional forces, the structure elements and the concrete pedestals must be oversized.
On the other hand, the photovoltaic panels also have a surface visible by people on the ground that is relatively significant. Consequently, these photovoltaic panels are in practice very visible by the public and might arouse interest of ill-intentioned people: theft, gunshot.
The device according to the invention proposes a solution that allows to remedy these drawbacks. In its principle, the invention consists in placing the photovoltaic panels on the top and the rear of the light display panel, horizontally or, preferably, with a slight inclination towards the rear and the bottom along an orientation that is hence independent of the zone of the sky where the solar luminosity is the highest. The slight inclination allows to avoid that wastes easily accumulate on the photovoltaic panels. The photovoltaic panels are then masked from the view of people on the ground by the light display panel. Moreover, they are positioned in an area in which they are practically in the plane of the portal post(s), which limits the cantilever. Their wind surface area is further reduced due to their low inclination and to the presence of the light display panel in front of them.
Structures of light display with photovoltaic panels are known from the documents CN103122613A, CN202530392U, ES1075234U. The documents EP1502999A1, U.S. Pat. No. 5,008,967A disclose portals, in particular for displays, with a catwalk open to the environment.